If we try to use the usual ipdb commands from a Jupyter (IPython
notebook)

importipdb;ipdb.set_trace()

we will get a similar error:

--------------------------------------------------------------------------MultipleInstanceErrorTraceback(mostrecentcalllast)<ipython-input-1-f2b356251c56>in<module>()1a=4---->2importipdb;ipdb.set_trace()3b=54printa5printb/home/nnn/anaconda/lib/python2.7/site-packages/ipdb/__init__.pyin<module>()14# You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.15--->16fromipdb.__main__importset_trace,post_mortem,pm,run,runcall,runeval,launch_ipdb_on_exception1718pm# please pyflakes/home/nnn/anaconda/lib/python2.7/site-packages/ipdb/__main__.pyin<module>()71# the instance method will create a new one without loading the config.72# i.e: if we are in an embed instance we do not want to load the config.--->73ipapp=TerminalIPythonApp.instance()74shell=get_ipython()75def_colors=shell.colors/home/nnn/anaconda/lib/python2.7/site-packages/traitlets/config/configurable.pycininstance(cls,*args,**kwargs)413raiseMultipleInstanceError(414'Multiple incompatible subclass instances of '-->415'%s are being created.'%cls.__name__416)417MultipleInstanceError:MultipleincompatiblesubclassinstancesofTerminalIPythonApparebeingcreated.